World tennis, already embattled from reports of match fixing, had new corruption allegations surface Tuesday. Two tennis umpires were secretly banned, while four others could be barred for life, for serious corruption, according to an investigative report from the Guardian.

The Guardian writes: 

Umpires from Kazakhstan, Turkey and Ukraine are among those alleged to have taken bribes from betting syndicates in exchange for manipulating live scores on the International Tennis Federation’s Futures Tour – which allowed crooked gamblers to place bets already knowing the outcome of the next point.

The report also alleged the International Tennis Federation (ITF) worked to keep quiet the cases of two umpires: one who was decertified for reaching out to another official in an attempt to manipulate the scoring of matches and another who was involved in gambling.

The report in the Guardian describes an alleged scheme that was carried out in ITF futures tournaments in Eastern Europe, a very low level of professional tennis with little media coverage and poorly paid or volunteer umpires. The ITF signed a deal with live-score service Sportradar in 2012, and under the terms of the deal, umpires were asked to update the scoreboard after each point using a tablet. This system transmitted results to bookmakers, which would update odds and prices as the match played out.

The umpires are alleged to have abused this system by delaying updating the score by up to one minute, which allowed gamblers to place bets on the in-play market before the odds were updated with the new score. Some umpires allegedly went as far as texting gamblers before updating the point.

"In terms of points settling games and sets, it would give gamblers inside knowledge ahead of bookmakers in getting more [favorable] odds and an advantage over the market," wrote Eurosport UK about the alleged scheme.

The report from the Guardian comes just weeks after former tennis player Nick Lindahl pleaded guilty to a match-fixing charge related to a minor tournament in 2013. That followed a lengthy January report from BuzzFeed and the BBC that alleged widespread match-fixing by players at the top-levels of tennis, including a Grand Slam winner. 

Read the full report from the Guardian here.